End effector knife design used in surgical tools

Abstract

The surgical tool includes a drive housing having opposing distal and proximal ends; a first drive cable and a second drive cable capstan disposed within the drive housing and asymmetrically aligned between the distal and proximal ends; a first drive cable extending distally from the drive housing and actuated by the movement of the first drive cable capstan; and a second drive cable extending distally from the drive housing and actuated by the movement of the second drive cable capstan. The stiffness of the first and second drive cables is equalized by adjusting one or more properties of one or both of the first and second drive cables.

Description

Background Art

[0001] Minimally invasive surgical (MIS) instruments are often preferred over conventional open surgical devices because they reduce postoperative recovery time and minimize scarring. Laparoscopic surgery is a type of MIS technique in which one or more small incisions are made in the patient's abdomen and trocars are inserted through the incisions to form a path for accessing the abdominal cavity. Through the trocars, various instruments and surgical tools can be introduced into the abdominal cavity. Using these instruments and tools introduced into the abdominal cavity through the trocars, tissue can be engaged and / or treated in many ways to obtain a diagnostic or therapeutic effect.

[0002] To assist MIS techniques, various robotic systems have been developed. The robotic system can enable intuitive hand movements by maintaining the natural line of sight and hand axis. The robotic system can also enable movement with multiple degrees of freedom by including a gimbal-like "wrist" joint that forms joints similar to those of a natural hand. In such a system, an end effector positioned at the distal end of the instrument can be articulated (moved) using a cable-driven motion system having one or more drive cables that extend through the wrist joint. A user (e.g., a surgeon) can remotely operate the end effector of the instrument by gripping and manipulating one or more controllers in space that communicate with a tool driver connected to the surgical instrument. The user input is processed by a computer system incorporated within the robotic surgical system, and the tool driver responds by actuating the cable-driven motion system. By moving the drive cables, the end effector is articulated to the desired angular position and configuration.

[0003] Some end effectors further include a knife that can move forward and backward between opposing jaws and cut or cleave the tissue grasped between the opposing jaws. Improvements in the design and function of the knife are desirable to improve the efficiency of the end effector and any procedures performed on it. [Brief explanation of the drawing]

[0004] The following figures are included to illustrate specific aspects of the disclosure, but should not be viewed as exclusive embodiments. The disclosed subject matter can be substantially modified, altered, combined, and equivalent in form and function without departing from the scope of the disclosure. [Figure 1] This is a block diagram of an exemplary robotic surgical system that may incorporate some or all of the principles of this disclosure. [Figure 2] This is an isometric side view of an exemplary surgical tool that may incorporate some or all of the principles of this disclosure. [Figure 3] Figure 2 shows the potential degrees of freedom of the wrist portion of the surgical tool, which can perform joint movement (pivot) and translation. [Figure 4] Figure 2 is a magnified isometric view of the distal end of the surgical tool. [Figure 5] This is another enlarged isometric view of the distal end of the surgical tool shown in Figure 2, according to one or more embodiments of the present disclosure. [Figure 6A] This is an enlarged isometric view of the knife and knife housing of Figure 5, according to one or more embodiments. [Figure 6B] This is an enlarged isometric view of the knife and knife housing of Figure 5, according to one or more embodiments. [Figure 7A] These are side and exploded isometric views of the distal end of the knife and drive rod according to one or more embodiments. [Figure 7B] These are side and exploded isometric views of the distal end of the knife and drive rod according to one or more embodiments. [Figure 8A]These are side and exploded isometric views of another embodiment of a knife, such that it is connected to the distal end of a drive rod, according to one or more additional embodiments. [Figure 8B] These are side and exploded isometric views of another embodiment of a knife, such that it is connected to the distal end of a drive rod, according to one or more additional embodiments. [Figure 9] This is an enlarged side view of an end effector having a firing knife, according to one or more embodiments. [Modes for carrying out the invention]

[0005] This disclosure relates to surgical tools, and more specifically to an end effector having improved knife mounting and functionality.

[0006] Embodiments discussed herein describe an end effector for a surgical tool, the end effector comprising opposing first and second jaws, and a knife slot defined in one or both of the first and second jaws. The knife is extendable through the knife slot and can be operably coupled to the knife rod in a retaining mechanism fixed to the distal end of a drive rod. More specifically, a central notch may be defined within the retaining mechanism, and the knife defines a locking mechanism receivable within the central notch for axially constraining the knife to the retaining mechanism and the knife rod. In at least one embodiment, the central notch extends into the material of the drive rod. Securing the knife to the drive rod in the locking mechanism and central notch may prove advantageous for transmitting axial loads from the knife to the drive rod, and thus may help prevent premature failure of the knife.

[0007] In some embodiments, the blade provides a blade at the front end of the knife and includes a front cutting edge that extends perpendicular to the sealing plane provided between the opposing first and second jaws when the opposing first and second jaws are closed, and an angled cutting edge that extends from the front cutting edge at a transition point. The angled cutting edge extends from the front cutting edge at an angle offset from perpendicular to the sealing plane. Having a front cutting edge perpendicular to the sealing plane can provide a longer stroke length for the knife.

[0008] In some embodiments, the rear end of the knife may have a shortened rear profile, defined by a first arched surface that extends from the top of the knife and transitions to a second arched surface that transitions to a third arched surface. A shortened rear profile may prove advantageous when the knife traverses a knife slot (which may be curved). Other knives without a shortened rear profile may catch or contact portions of the curved knife slot, but a shortened rear profile eliminates the inefficiency that would cause this friction.

[0009] Figure 1 is a block diagram of an exemplary robotic surgical system 100 that may incorporate some or all of the principles of this disclosure. As shown, the system 100 may include at least one set of user input controllers 102a and at least one control computer 104. The control computer 104 may be mechanically and / or electrically connected to a robotic manipulator, more specifically, one or more robotic arms 106 (alternatively referred to as “tool drive units”). In some embodiments, the robotic manipulator may be contained in or otherwise mounted on an arm cart that may make the system portable. Each robotic arm 106 may include, or otherwise provide, a place to mount one or more surgical instruments or tools 108 for performing various surgical tasks on a patient 110. The operation of the robotic arms 106 and associated tools 108 may be instructed by a clinician 112a (e.g., a surgeon) from the user input controllers 102a.

[0010] In some embodiments, a second set of user input controllers 102b (shown by dashed lines) may be operated by the second clinician 112b in conjunction with the first clinician 112a to instruct the operation of the robotic arm 106 and tool 108 via the control computer 104. In such embodiments, for example, each clinician 112a,b may control a different robotic arm 106, or, as appropriate, complete control of the robotic arm 106 may be passed between clinicians 112a,b as needed. In some embodiments, an additional robotic manipulator with additional robotic arms may be used during surgery on patient 110, and these additional robotic arms may be controlled by one or more of the user input controllers 102a,b.

[0011] The control computer 104 and user input controllers 102a,b may communicate with each other according to any communication protocol via a communication link 114, which may be any type of wired or wireless telecommunications means configured to carry various communication signals (e.g., electrical, optical, infrared, etc.). In some applications, for example, there may be a tower equipped with auxiliary devices and a processing core designed to drive a robotic arm 106.

[0012] The user input controllers 102a,b generally include one or more physical controllers that clinicians 112a,b can grasp and manipulate in space while the surgeon views the procedure via a stereo display. The physical controllers generally include manual input devices that are movable in multiple degrees of freedom, and the manual input devices often include actuated handles for operating surgical tools 108 (e.g., for opening and closing opposing jaws, applying potential (current) to electrodes, etc.). To provide a visual display of various surgical instrument metrics, such as the amount of force applied to the surgical instrument (i.e., cutting instrument or dynamic clamping member), the control computer 104 may further include optional feedback meters that clinicians 112a,b can view via a display.

[0013] Figure 2 is an isometric side view of an exemplary surgical tool 200 that may incorporate some or all of the principles of this disclosure. The surgical tool 200 may be identical or similar to the surgical tool 108 in Figure 1, and therefore may be used in conjunction with a robotic surgical system, such as the robotic surgical system 100 in Figure 1. Accordingly, the surgical tool 200 may be designed to be releasably coupled to a tool drive unit included in the robotic surgical system 100. However, in other embodiments, the form of the surgical tool 200 may be adapted for use in a manual or hand-operated manner without departing from the scope of this disclosure.

[0014] As shown in the figure, the surgical tool 200 includes an elongated shaft 202, an end effector 204, a wrist portion 206 (alternatively referred to as the “wrist joint” or “articulated wrist joint”) connecting the end effector 204 to the distal end of the shaft 202, and a drive housing 208 connected to the proximal end of the shaft 202. In applications where the surgical tool is used with a robotic surgical system (e.g., the robotic surgical system 100 in Figure 1), the drive housing 208 may include a coupling mechanism that releasably connects the surgical tool 200 to the robotic surgical system.

[0015] The terms “proximal” and “distal” are defined herein in reference to a robotic surgical system having an interface configured to mechanically and electrically connect a surgical tool 200 (e.g., housing 208) to a robotic manipulator. The term “proximal” refers to the location of an element closer to the robotic manipulator, and the term “distal” refers to the location of an element closer to the end effector 204 and therefore further away from the robotic manipulator. Alternatively, in applications operated manually or by hand, the terms “proximal” and “distal” are defined herein in reference to a user, such as a surgeon or clinician. The term “proximal” refers to the location of an element closer to the user, and the term “distal” refers to the location of an element closer to the end effector 204 and therefore further away from the user. Furthermore, the use of directional terms such as up, down, upward, downward, left, right, etc., is used in reference to illustrative embodiments as shown in the figures, where upward or upward direction is toward the top of the corresponding figure, and downward or downward direction is toward the bottom of the corresponding figure.

[0016] During use of the surgical tool 200, the end effector 204 is configured to move (pivot) relative to the shaft 202 at the wrist portion 206 to position the end effector 204 in a desired direction and location relative to the surgical site. To achieve this, the housing 208 includes (houses) various drive inputs and mechanisms (e.g., gears, actuators, etc.) designed to control the operation of various mechanisms associated with the end effector 204 (e.g., clamping, firing, cutting, rotating, jointing, etc.). In at least some embodiments, the shaft 202, and therefore the end effector 204 connected thereto, is configured to rotate about the longitudinal axis A1 of the shaft 202. In such embodiments, at least one of the drive inputs contained in the housing 208 is configured to control the rotational motion of the shaft 202 about the longitudinal axis A1.

[0017] The shaft 202 is an elongated member extending distally from the housing 208 and has at least one lumen extending through its interior along its axial length. In some embodiments, the shaft 202 may be fixed to the housing 208, but alternatively, it may be rotatably mounted to the housing 208 so as to allow the shaft 202 to rotate around the longitudinal axis A1. In yet another embodiment, the shaft 202 may be releasably connected to the housing 208, thereby allowing a single housing 208 to be adapted to various shafts having different end effectors.

[0018] The end effector 204 can exhibit a variety of sizes, shapes, and configurations. In the illustrated embodiment, the end effector 204 comprises a tissue gripper and vessel sealer combination including opposing first (upper) jaws 210 and opposing second (lower) jaws 212 configured to move (articulate) between an open position and a closed position. However, as will be understood later, the opposing jaws 210, 212 may alternatively form part of other types of end effectors, including but not limited to surgical scissors, clip applicators, needle holders, Babcocks including a pair of opposing gripping jaws, and bipolar jaws (e.g., bipolar Maryland gripping instruments, forceps, fenestrated gripping instruments, etc.). One or both of the jaws 210, 212 may be configured to pivot in order to articulate the end effector 204 between an open position and a closed position.

[0019] Figure 3 shows the potential degrees of freedom in which the wrist 206 can perform articulating motion (pivoting) to move the end effector 204. The wrist 206 can have any of a variety of configurations. Generally, the wrist 206 includes joints configured to enable pivoting motion of the end effector 204 relative to the shaft 202. The degrees of freedom of the wrist 206 are represented by three translational variables (i.e., surge, heave, and sway), as well as by three rotational variables (i.e., Euler angles or roll, pitch, and yaw). The translational and rotational variables describe the position and orientation of the end effector 204 relative to a given reference Cartesian frame. As shown in Figure 3, "surge" refers to translational motion in the forward and backward directions, "heave" refers to translational motion in the up and down directions, and "sway" refers to translational motion in the left and right directions. For rotational terms, "roll" means tilting the side, "pitch" means tilting forward and backward, and "yaw" refers to rotating left and right.

[0020] The pivoting motion can include pitch motion about a first axis (e.g., the X axis) of the wrist 206, yaw motion about a second axis (e.g., the Y axis) of the wrist 206, and combinations thereof, enabling 360° rotational motion of the end effector 204 around the wrist 206. In other applications, the pivoting motion can be limited to motion within a single plane, e.g., only pitch motion about the first axis of the wrist 206 or only yaw motion about the second axis of the wrist 206, such that the end effector 204 moves only within a single plane.

[0021] Referring again to FIG. 2, the surgical tool 200 may further include a plurality of drive cables (hidden in FIG. 2) that form part of a cable-driven motion system configured to facilitate the actuation and articulation of the end effector 204 relative to the shaft 202. By moving (actuating) one or more of the drive cables, the end effector 204 moves between a non-articulated position and an articulated position. In FIG. 2, the longitudinal axis A2 of the end effector 204 is shown in a non-articulated position where it is substantially aligned with the longitudinal axis A1 of the shaft 202, such that the angle of the end effector 204 relative to the shaft 202 is substantially zero. Due to factors such as manufacturing tolerances and accuracy of the measuring device, the end effector 204 may not be at an exact zero angle relative to the shaft 202 in the non-articulated position, but may still be considered "substantially aligned" with the shaft 202. In the articulated position, the longitudinal axes A1, A2 will be angularly offset from each other such that the angle of the end effector 204 relative to the shaft 202 is non-zero.

[0022] In some embodiments, power (current) may be supplied to the surgical tool 200 via a power cable 214 connected to the housing 208. In other embodiments, the power cable 214 may be omitted, and power may be supplied to the surgical tool 200 via an internal power source such as one or more batteries or a fuel cell. In such embodiments, the surgical tool 200 may alternatively be characterized as an "electrosurgical instrument" capable of supplying electrical energy to the end effector 204 and may be referred to as such.

[0023] The power cable 214 can allow the surgical tool 200 to communicate with the generator 216, which supplies energy such as electrical energy (e.g., radio frequency energy), ultrasonic energy, microwave energy, thermal energy, or any combination thereof, to the surgical tool 200, more specifically to the end effector 204. Thus, the generator 216 may be equipped with a radio frequency (RF) source, an ultrasonic source, a DC source, and / or any other suitable type of electrical energy source, which can be activated independently or simultaneously.

[0024] In applications where the surgical tool 200 is configured for bipolar operation, the power cable 214 includes a supply conductor and a return conductor. Current can be supplied from the generator 216 to the active (or source) electrode located at the end effector 204 via the supply conductor, and current can return to the generator 216 via the return conductor located at the end effector 204. In the case of a bipolar gripping instrument with opposing jaws, for example, the jaws are isolated from each other at their proximal ends, and the inner surfaces of the jaws (i.e., the areas of the jaws that grip tissue) function as electrodes that apply current in a controlled path through the tissue. In applications where the surgical tool 200 is configured for unipolar operation, the generator 216 transmits current via the supply conductor to the active electrode located at the end effector 204, and the current is returned (dissipated) via a return electrode (e.g., a grounding pad) separately connected to the patient's body.

[0025] The surgical tool 200 may further include a manual release switch 218 that can be manually operated by a user (e.g., a surgeon) to open the jaws 210, 212. The release switch 218 is movably positioned on the drive housing 208, and the user can manually move (slide) the release switch 218 from the disengaged position to the engaged position, as shown. In the disengaged position, the surgical tool 200 can operate normally. However, when the release switch 218 is moved to the engaged position, various internal components of the drive housing 208 move simultaneously, causing the jaws 210, 212 to open, which may prove beneficial for various reasons. In some applications, for example, the release switch 218 can be moved if an electrical failure occurs that renders the surgical tool 200 inoperable. In such applications, the user can manually open the jaws 210, 212, release the grasped tissue, and remove the surgical tool 200. In other applications, the release switch 218 may be activated (made available) to open the jaws 210, 212 in preparation for cleaning and / or sterilization of the surgical tool 200. In some applications, the surgical tool 200 is first separated from the robotic manipulator and associated motors, and then the user can activate the manual release switch 218 to move the associated inputs and drive the cables once the motors are disengaged.

[0026] Figure 4 is a magnified isometric view of the distal end of the surgical tool 200. More specifically, Figure 4 shows a magnified view of the end effector 204 and wrist portion 206 with the jaws 210, 212 of the end effector 204 in the closed position. The wrist portion 206 operably connects the end effector 204 to the shaft 202. However, in some embodiments, the shaft adapter may be directly connected to the wrist portion 206, or otherwise interposed between the shaft 202 and the wrist portion 206. Thus, the wrist portion 206 may operably connect to the shaft 202 through either a direct connection engagement in which the wrist portion 206 is directly connected to the distal end of the shaft 202, or an indirect connection engagement in which the shaft adapter is interposed between the wrist portion 206 and the distal end of the shaft 202. As used herein, the term “operably connected” refers to a direct or indirect connection engagement between two components.

[0027] To operably connect the end effector 204 to the shaft 202, the wrist portion 206 includes a first or "distal" clevis 402a and a second or "proximal" clevis 402b. The clevises 402a,b are alternatively referred to as the "articular joints" of the wrist portion 206 and extend from the shaft 202, or alternatively from the shaft adapter. The clevises 402a,b are operably connected to facilitate the articular movement of the wrist portion 206 relative to the shaft 202. As shown in the figure, the wrist portion 206 further includes a linkage mechanism 404 located distal to the distal clevis 402a and operably attached to the jaws 210, 212.

[0028] As shown in the figure, the proximal end of the distal clevis 402a may be rotatably attached to or pivotally connected to the proximal clevis 402b on the first pivot axis P1 of the wrist portion 206. In some embodiments, the axis may extend through the first pivot axis P1, and the distal and proximal clevises 402a,b may be rotatably connected via the axis. However, in other embodiments, such as those shown in Figure 4, the distal and proximal clevises 402a,b may be engaged in rolling contact, such as via a meshing gear relationship that allows the clevises 402a,b to rotate relative to each other, similar to a rotary joint.

[0029] The first pulley 406a and the second pulley 406b can be rotatably mounted to the distal end of the distal clevis 402a on the second pivot axis P2 of the wrist portion 206. A linkage mechanism 404 is located distal to the second pivot axis P2 and can be operably mounted to the jaws 210, 212. The first pivot axis P1 is substantially perpendicular (orthogonal) to the longitudinal axis A1 of the shaft 202, and the second pivot axis P2 is substantially perpendicular (orthogonal) to both the longitudinal axis A1 and the first pivot axis P1. Movement of the end effector 204 around the first pivot axis P1 provides "yaw" joint movement of the wrist portion 206, and movement around the second pivot axis P2 provides "pitch" joint movement of the wrist portion 206.

[0030] The multiple drive cables, indicated as drive cables 408a, 408b, 408c, and 408d, extend longitudinally within a lumen 410 defined by a shaft 202 (or shaft adapter), and extend at least partially through a wrist portion 206. The drive cables 408a-d may form part of a cable-driven motion system housed within a drive housing 208 (Figure 2), and may include cables, bands, lines, cords, wires, woven wires, ropes, strings, twisted strings, elongated members, belts, shafts, flexible shafts, drive rods, or any combination thereof. The drive cables 408a-d can be made from a variety of materials, including but not limited to metals (e.g., tungsten, stainless steel, nitinol, etc.), polymers (e.g., ultra-high molecular weight polyethylene), synthetic fibers (e.g., KEVLAR®, VECTRAN®, etc.), elastomers, or any combination thereof. Four drive cables 408a to d are shown in Figure 4, but more than four or fewer than four cables can be used without departing from the scope of this disclosure.

[0031] The drive cables 408a to d extend proximal to the drive housing 208 (Figure 2) from the end effector 204 and wrist portion 206, and are operably connected to various operating mechanisms or devices to facilitate the longitudinal movement (translation) of the drive cables 408a to d within the lumen 410. Selective operation of the drive cables 408a to d is achieved by applying tension (i.e., tensile force) to a given drive cable 408a to d in a proximal direction, thereby biasing the given drive cables 408a to d and causing them to translate longitudinally within the lumen 410.

[0032] In the illustrated embodiment, the drive cables 408a to 408d each extend longitudinally through the proximal clevis 402b. The distal ends of each drive cable 408a to 408d are terminated at the first pulley 406a or the second pulley 406b, thus operably connecting each drive cable 408a to 408d to the end effector 204. In some embodiments, the distal ends of the first drive cable 408a and the second drive cable 408b may be connected to each other and terminated at the first pulley 406a, and the distal ends of the third drive cable 408c and the fourth drive cable 408d may be connected to each other and terminated at the second pulley 406b. In at least one embodiment, the distal ends of the first drive cable 408a and the second drive cable 408b, and the distal ends of the third drive cable 408c and the fourth drive cable 408d, may be connected to each other by corresponding ball crimps (not shown) attached to the first pulley 406a and the second pulley 406b, respectively.

[0033] In at least one embodiment, the drive cables 408a to 408d may operate "antagonistically". More specifically, when the first drive cable 408a is actuated (moved), the second drive cable 408b follows naturally because it is connected to the first drive cable 408a, and when the third drive cable 408c is actuated, the fourth drive cable 408d follows naturally because it is connected to the third drive cable 408c, and vice versa. The antagonistic operation of the drive cables 408a to 408d can open and close the jaws 210 and 212, and further, can articulate the end effector 204 at the wrist portion 206. More specifically, the selective operation of the drive cables 408a to 408d in known configurations or combinations can articulate the end effector 204 around one or both of the pivot axes P1 and P2, thus facilitating articulation of the end effector 204 in both the pitch and yaw directions. Furthermore, the selective operation of drive cables 408a-d in other known configurations or combinations causes jaws 210 and 212 to open and close. The antagonistic operation of drive cables 408a-d advantageously reduces the number of cables required to provide full movement of the wrist section 206, helps eliminate slack in drive cables 408a-d, and results in more precise movement of the end effector 204.

[0034] In the illustrated embodiment, the end effector 204 can articulate (move) in a pitch manner about a second or "pitch" pivot axis P2 located near the distal end of the wrist portion 206. This causes the jaws 210 and 212 to open and close in the pitch direction. However, in other embodiments, the wrist portion 206 may be configured, without departing from the scope of the present disclosure, to facilitate yaw articulation of the jaws 210 and 212 about the second pivot axis P2.

[0035] In some embodiments, the electrical conductor 412 can further extend longitudinally within the lumen 410, pass through the wrist portion 206, and terminate at the electrode 414 to supply electrical energy to the end effector 204. In some embodiments, the electrical conductor 412 may include a wire, but alternatively, it may include a rigid or semi-rigid shaft, rod, or strip (ribbon) made of a conductive material. The electrical conductor 412 may be covered entirely or partially with an insulating coating (overmolding) made of a non-conductive material. Using the electrical conductor 412 and the electrode 414, the end effector 204 may be configured for unipolar or bipolar RF operation.

[0036] In the illustrated embodiment, the end effector 204 comprises a combination of a tissue gripper and a vascular sealer, including a knife (invisible) which may be substituted for a “cutting element” or “blade.” The knife is configured to align with and traverse a guide track or “knife slot” (invisible) longitudinally defined on one or both of the upper jaw 210 and the lower jaw 212. The knife may be operably connected to the distal end of a drive rod 416 (alternatively referred to as a “knife rod,” “actuator rod,” or “push rod”) which extends longitudinally within the lumen 410 and passes through the wrist portion 206. The longitudinal movement (translation) of the drive rod 416 corresponds to the movement of the knife within the knife slot. Similar to the drive cables 408a-d, the drive rod 416 may form part of an actuation system housed within the drive housing 208 (Figure 2). The selective action of the corresponding drive input moves the drive rod 416 distally or proximal within the lumen 410, and in turn moves the knife in the same longitudinal direction.

[0037] The drive rod 416 may comprise a rigid or semi-rigid elongated member such as a rod or shaft (e.g., hypotube, hollow rod, solid rod, etc.), wire, ribbon, push cable, or any combination thereof. The drive rod 416 can be made from a variety of materials, including but not limited to metals (e.g., tungsten, nitinol, stainless steel, etc.), polymers, or composite materials. The drive rod 416 may have a circular cross-section, but alternatively, without departing from the scope of this disclosure, it may have a polygonal cross-section.

[0038] Figure 5 is another enlarged isometric view of the end effector 204 according to one or more embodiments of the present disclosure. The upper jaws 210 (Figures 2 and 4) are omitted from Figure 5 to allow viewing of the various internal mechanisms of the end effector 204.

[0039] In the illustrated embodiment, the knife 502 (mostly closed) is shown as being received within a portion of the electrode 414 of the lower jaw 212, more specifically, within a portion of the insulator 504 connected to the electrode 414. In the subsequently retracted position, as shown in Figure 5, the knife 502 may further be partially received within a knife housing 506 mounted on the end effector 204 between the upper jaw 210 and the lower jaw 212. The lower jaw 212 provides or otherwise defines a knife slot 508, through which the knife 502 may traverse during distal operation of the drive rod 416. Although the knife slot 508 is shown as being provided by the lower jaw 212, in some embodiments the knife slot 508 may be collaboratively defined by both the upper jaw 210 and the lower jaw 212.

[0040] As described in more detail below, the knife housing 506 may define a central passage through which a drive rod 416 extends to move the knife 502 along the knife slot 508. When the end effector 204 is fired, the drive rod 416 is moved distally (biased), and in response, the knife 502 moves out of the knife housing 506 into the knife slot 508. After firing is complete, the drive rod 416 retracts proximally, pulling the knife 502 proximally back into the knife housing 506 until it is desired to fire the end effector 204 again.

[0041] Figures 6A and 6B are enlarged isometric views of the knife 502 and knife housing 506 according to one or more embodiments. In Figure 6A, the knife 502 is shown in a first position or “retained” position, where the knife 502 is at least partially received within a cavity 602 defined by the knife housing 506 and is sized to receive and “retain” the knife 502 when not in use. In Figure 6B, the knife 502 is shown in a second position or “extended” position, where the knife 502 extends distally from the cavity 602.

[0042] As described above, the knife 502 can be operably connected to the distal end of the drive rod 416 (shown by a dashed line in Figure 6A). The central passage 604 is defined through the knife housing 506 and provides a conduit through which the drive rod 416 can move the knife 502 into and along the knife slot 508 (Figure 5). In at least one embodiment, the lumen 602 may form part of the central passage 604 or communicate with the central passage. In some embodiments, the drive rod 416 may comprise a solid shaft, but alternatively, it may comprise a tube or tubular structure. Furthermore, the drive rod 416 may be made from a variety of flexible materials, including but not limited to metals or metal alloys (e.g., nickel-titanium alloy or "nitinol"), plastics or thermoplastic materials, composite materials, or any combination thereof. The drive rod 416 may further comprise a braided cable structure made of metal (e.g., stainless steel, tungsten, etc.) or one of the aforementioned materials, and such a braided cable may be radially constrained to support an axial load.

[0043] In some embodiments, as shown, the flexible sheath 606 (e.g., a hypotube) can cover at least a portion of the drive rod 416. The sheath 606 can help support the drive rod 416 and prevent buckling when subjected to compressive loads during joint movement of the wrist portion 206 (Figures 2 and 4) and during opening and closing of the jaws 210, 212 (Figures 2 and 4). Like the drive rod 416, the flexible sheath 606 may be made from a variety of flexible materials, including but not limited to metals or metal alloys (e.g., nickel-titanium alloy or "nitinol"), metal coils, plastics or thermoplastic materials, composite materials, braided tubular materials, or any combination thereof.

[0044] The knife 502 may be attached to the distal end of the drive rod 416 in a connecting or “retaining” mechanism 608. The retaining mechanism 608 may include any mounting or coupling means for removably or permanently securing the knife 502 to the drive rod 416. For example, the retaining mechanism 608 may include, but is not limited to, crimp engagements, weld interfaces, adhesive mountings, press-fits or shrink-fits, overmoldings (e.g., molded material blocks or support blocks), one or more mechanical fasteners, or any combination thereof. In at least one embodiment, the retaining mechanism 608 may include a metal tube crimped or press-fitted to the distal end of the drive rod 416.

[0045] When the end effector 204 (Figures 2 and 4) is fired, the drive rod 416 is moved distally (biased) through the central passage 604, correspondingly moving the knife 502 to its extended position, or otherwise moving it out of the cavity 602 into the knife slot 508 (Figure 5). As the drive rod 416 is translated distally, the sheath 606 supports the drive rod 416 against axial buckling resulting from the compressive load on the drive rod 416. After firing is complete, the drive rod 416 retracts proximally, correspondingly pulling the knife 502 proximally back to its retracted position, or otherwise retracting it into the cavity 602, until it is desired to fire the end effector 204 again.

[0046] Some end effectors, such as the end effector 204 in Figures 2 and 4, can articulate simultaneously in two planes, requiring the knife 502 and drive rod 416 to traverse the articulated joint while still applying appropriate cutting force. Furthermore, moving the knife 502 in the retraction direction may result in a hard stop, retraction overdrive prevention, or contact with a position locator to be supplied to a manufacturing setup or control scheme. In some cases, this may cause the knife 502 to fail prematurely and otherwise separate from the retaining mechanism 608 and / or drive rod 416. According to embodiments of the present disclosure, as will be described in more detail below, the knife 502 may be operably coupled to the retaining mechanism 608 and drive rod 416 using a mechanical locking mechanism, which helps to accommodate any resulting axial loads, including retraction, retraction overdrive prevention, and positioning loads.

[0047] Figures 7A and 7B are side and exploded isometric views, respectively, of a knife 502 connected to the distal end of a drive rod 416 according to one or more embodiments. As shown, the retaining mechanism 608 may be fixed to the distal end of the drive rod 416. The retaining mechanism 608 may be made of a material that allows the knife 502 to be welded to the retaining mechanism. In at least one embodiment, for example, the retaining mechanism 608 may be made of a metal such as stainless steel. In embodiments in which the knife 502 is made of nitinol, the retaining mechanism 608 may also be made of nitinol.

[0048] As shown in the figure, the retaining mechanism 608 may comprise a short tubular length or tube. More specifically, the retaining mechanism 608 may comprise a tubular body 702 having a first end or “distal” end 704a and a second end or “proximal” end 704b opposite the distal end 704a. The tubular body 702 may provide an internal conduit or passage sized to receive the distal end of the drive rod 416a. As described above, the body 702 of the retaining mechanism 608 may be fixed to the drive rod 416 by a variety of methods including, but not limited to, crimping, press-fitting, shrink-fitting, adhesive, or any combination thereof.

[0049] When the retaining mechanism 608 is fixed to the distal end of the drive rod 416, a central notch 706 may be cut into the body 702 at a position between the distal end 704a and the proximal end 704b, and otherwise defined. As shown in the figure, the central notch 706 may partially extend through the side wall of the body 702 into the material beneath the drive rod 416. In some embodiments, the central notch 706 may be defined and formed otherwise through grinding, but alternatively, it may be formed through other processes such as laser cutting, wire electrical discharge machining (EDM), milling, chemical etching, water jetting, and stamping. In some embodiments, the depth of the central notch 706 into the material of the drive rod 416 may stop before the centerline of the drive rod 416. However, in other embodiments, the depth of the central notch 706 may extend beyond the centerline of the drive rod 416 without departing from the scope of the present disclosure.

[0050] In some embodiments, as illustrated, the knife 502 may provide, or otherwise define, a locking mechanism 708 sized or configured to be received within a central notch 706 when the knife 502 is properly mounted to the holding mechanism 608. In one or more embodiments, the locking mechanism 708 may be laser-cut into the body of the knife 502, but alternatively, without departing from the scope of the present disclosure, it may be defined by other manufacturing or forming processes.

[0051] In the illustrated embodiment, the locking mechanism 708 comprises a substantially rectangular projection or tab extending from the bottom of the body of the knife 502. However, in other embodiments, the locking mechanism 708 may have other geometric shapes, including, but not limited to, angled, arched, rounded, or any combination thereof. In some embodiments, when the knife 502 is attached to the retaining mechanism 608, the locking mechanism 708 may extend into the central notch 706 but not in contact with the bottom of the central notch 706, such as the material of the drive rod 416. In such embodiments, a gap 712 may be defined between the bottom of the central notch 706 and the outer extent of the locking mechanism 708. However, in other embodiments, the locking mechanism 708 may be designed and otherwise configured to contact the bottom of the central notch 706 or to rest on it.

[0052] As best seen in Figure 7A, once the locking mechanism 708 is received within the central notch 706, the knife 502 can be welded to the outer surface of the retaining mechanism 608 at one or more locations. More specifically, the knife 502 can be welded to the retaining mechanism 608 at a first weld 710a located distal to the central notch 706, and a second weld 710a located proximal to the central notch 706. However, in other embodiments, one of the welds 710a,b may be omitted without departing from the scope of the present disclosure. In some applications, the gap 712 may prove advantageous in ensuring close (direct) contact between the retaining mechanism 608 and the blade 502, and may facilitate stronger welds 710a,b.

[0053] In some embodiments, the length L1 of the distal weld 710a may be shorter than the length L2 of the proximal weld 710b. This may prove advantageous because the stress concentration region of the drive rod 416 (e.g., the proximal notch corner) is further away from where the drive rod 416 exits the retaining mechanism 608, and as a result is less subjected to bending loads (from articulation and retraction) further away from the proximal edge. In addition, retraction loads generally result in primary loads in the proximal region of the weld, and therefore having a more robust (longer) proximal weld may help reduce the separation of the knife 502 from the retaining mechanism 608. However, in other embodiments, without departing from the scope of the present disclosure, the length L1 of the distal weld 710a may be longer than the length L2 of the proximal weld 710b, or the lengths L1 and L2 may be the same.

[0054] In some embodiments, the length from the proximal end of the central notch 716 to the proximal end of the retaining mechanism 608 may be longer than the length from the distal end of the central notch 706 to the distal end of the retaining mechanism 608. This may be helpful in accommodating a longer length L2 to a shorter length L1, but it may also prove advantageous in helping fatigue life because the greater length between the bending flexibility region of the knife rod 416 and the region of the central notch 706.

[0055] In at least one embodiment, the locking mechanism 708 may be received within the central notch 706 such that the distal end 714a of the locking mechanism 708 contacts and otherwise engages with the opposing distal end 714b of the central notch 706, thereby axially restraining the knife 502 to the retaining mechanism 608 and the drive rod 416. More specifically, engaging the opposing distal ends 714a,b may prove advantageous in transmitting axial loads from the knife 502 to the drive rod 416, and thus help prevent premature failure of the knife 502, for example, separation of the knife 502 from the retaining mechanism 608. More specifically, when the knife 502 is positioned or retracted, as briefly described above, the knife 502 moves proximal and is housed within the knife housing 506 (Figures 6A-6B). During retraction after firing or during the positioning sequence, an axial load is applied to the drive rod 416 to retract the knife 502 and / or engage the knife 502 axially with the knife housing 506. By bringing the opposing distal ends 714a and 714b into contact, the knife 502 can directly transmit the resulting axial load caused by contact with the knife housing 506 to the drive rod 416. If the opposing distal ends 714a and 714b are not in contact, the resulting axial load applied to the knife 502 is absorbed by the welds 710a and 710b, which can separate the knife 502 from the holding mechanism 608.

[0056] Therefore, while the welds 710a and 710b may help to restrain the knife 502 perpendicularly to the drive rod 416 via the retaining mechanism 608, receiving the locking mechanism 708 within the central notch 706 may provide additional axial restraint and load transmission that helps prevent the knife 502 from prematurely separating from the drive rod 416. As a result, the locking mechanism 708 allows for higher and increased retraction, prevention of retraction overdrive, and maintenance of the positioning load.

[0057] As best seen in Figure 7B, in some embodiments the end notch 716 may be cut into and otherwise defined in the distal end of the drive rod 416. As shown, the end notch 716 may partially extend into the material of the drive rod 416, passing through the distal end 704a of the retaining mechanism 608. The end notch 716 may be defined and otherwise formed by any of the processes described above for forming the central notch 706. In at least one embodiment, as shown, the end notch 716 may extend perpendicular to the central notch 706.

[0058] In some embodiments, as best shown in Figure 7B, the knife 502 may provide an end tab 718 sized to be received within an end notch 716, or otherwise defined. Receiving the end tab 718 within the end notch 716 may help to stabilize the knife 502 laterally when mounted on the retaining mechanism 608. Furthermore, receiving the end tab 718 within the end notch 716 may prove advantageous for directly transmitting axial loads in the firing direction from the drive rod 416 to the end tab 718. In at least one embodiment, the knife 502 may be further welded to the distal end of the drive rod 416 at the interface between the end tab and the end notch 716.

[0059] Figures 8A and 8B are side and exploded isometric views, respectively, of another embodiment of the knife 502, which is connected to the distal end of the drive rod 416, according to one or more additional embodiments. The knife 502 shown in Figures 8A and 8B may be similar in some respects to the knife 502 in Figures 7A and 7B, and can therefore be best understood by referring to it, with similar reference numerals corresponding to similar components which will not be described in detail again.

[0060] Similar to the knife 502 in Figures 7A-7B, for example, the knife 502 in Figures 8A-8B includes a retaining mechanism 608 fixed to the distal end of the drive rod 416, and a central notch 706 is defined within the retaining mechanism 608 and may partially extend into the material beneath the drive rod 416. Furthermore, the knife 502 provides a locking mechanism 708 sized to receive within the central notch 706, and the knife 502 may be fixed to the outer surface of the retaining mechanism 608 using one or both of the welds 710a, b (see Figure 8A), generally as described above. Furthermore, an end tab 718 provided by the knife 502 may be received within an end notch 716 defined at the distal end of the drive rod 416 and the retaining mechanism 608.

[0061] However, unlike the knife 502 in Figures 7A-7B, the knife 502 in Figures 8A-8B may include a double blade 802 provided at the distal or "front" end 804a of the knife 502. The blade 802 is the sharp portion of the knife 502 opposite the proximal or "rear" end 804b of the knife 502 and is configured to cut, or otherwise sever, tissue as the end effector 204 (Figures 2 and 4) fires and advances the knife 502 during operation. In the illustrated embodiment, the blade 802 may include a first cutting edge or "front" cutting edge 806a and a second cutting edge or "angled" cutting edge 806b extending from the front cutting edge 806a at a transition point 808.

[0062] The front cutting edge 806a may extend substantially perpendicular or perpendicular to the centerline 810 of the drive rod 416. Furthermore, as will be described in more detail below, the front cutting edge 806b may further extend perpendicular to the sealing plane of the end effector 204 (Figures 2 and 4). As is best seen in Figure 8A, the angled cutting edge 806b extends from the front cutting edge 806a at the transition point 808 at an angle 812 offset from perpendicular to the centerline 810 (or the sealing plane of the end effector 204). The angle 812 may be in the range of about 1° to about 60°, and any subset therein.

[0063] In some embodiments, the transition point 808 may have a sharp corner or transition between the forward and angled cutting edges 806a, b. However, in other embodiments, the transition point may have an arched or curved transition between the forward and angled cutting edges 806a, b without departing from the scope of the present disclosure.

[0064] Briefly referring to Figure 9, an enlarged side view of an end effector 204 having a knife 502 in firing order is shown according to one or more embodiments. More specifically, the end effector 204 is shown by dashed lines in Figure 9, thus allowing a view of the knife 502 in firing order, otherwise the knife 502 advancing distally (or proximal) within the knife slot 508 (Figure 5).

[0065] As shown in the figures, the end effector 204 includes an upper jaw 210 and a lower jaw 212, and a gap 902 is defined between the upper jaw 210 and the lower jaw 212 when the jaws 210 and 212 are closed. The upper jaw 210 provides an upper surface 904a, and the lower jaw 212 provides an opposite lower surface 904b. The lower surface 904b may have the same structure as the electrode 414 (Figures 4 and 5) attached to or forming part of the lower jaw 212. In some embodiments, the upper surface 904a may further include an electrode, or otherwise include a planar sealing plane made of a non-conductive material (e.g., an insulator).

[0066] As shown in Figure 9, when the jaws 210 and 212 are in the closed position, the upper surface 904a and the lower surface 904b face each other and cooperate to form a sealing plane 906 that extends through the gap 902. The sealing plane 906 is positioned to grip the tissue between the upper jaw 210 and the lower jaw 212 in preparation for cutting by the knife 502, and is therefore alternatively referred to as the “tissue capture section”. As shown, when the knife 502 traverses the knife slot 508 (Figure 5), the front cutting edge 806a extends substantially perpendicular to the sealing plane 906.

[0067] In some embodiments, as illustrated, the entire front cutting edge 806a may be located below the sealing plane 906 and within a knife slot 508 (Figure 5) defined within the lower jaw 212. In such embodiments, the transition point 808 may be located further below the sealing plane 906. However, in other embodiments, without departing from the scope of the present disclosure, it is assumed that the front cutting edge 806a may extend to or above the sealing plane 906, and thus provide a transition point 808 further to or above the sealing plane 906. In any scenario, the front cutting edge 806a may be located to cut tissue that may be located below the sealing plane 806, such as tissue that can be moved or “constricted” into the knife slot 508 when the jaws 210, 212 are closed. Furthermore, this specification also envisions modifying the arrangement of the front cutting edge 806a and the angled cutting edge 806b such that the angled cutting edge 806b is positioned entirely below the sealing plane 906, and only the front cutting edge 806a is located within the sealing plane 906.

[0068] In 906, the forward cutting edge 806a, which is perpendicular to the sealing plane, may further prove advantageous in providing a longer stroke length for the knife 502. More specifically, other knife designs, such as the knife 502 shown in Figures 7A-7B, exhibit a fully angled cutting edge (extending from top to bottom) that extends distally beyond the distal position of the forward cutting edge 806a. As can be understood, this may limit the distance the knife 502 can advance within the knife slot 508 (Figure 5) because the angled bottom or “tip” of the fully angled cutting edge engages with the distal end of the knife slot 508. This may further lead to breakage of the tip of the fully angled cutting edge by repeated engagement with the distal end of the knife slot 508. Furthermore, the tip may cause friction as the knife 502 traverses the curvature of the knife slot 508. In contrast, the forward cutting edge 806a extends perpendicular to the sealing plane 906, resulting in a reduction in the effective length of the knife 502 and thus increasing the potential overall cutting length of the knife 502 along the knife slot 508.

[0069] Referring again to Figures 8A–8B, unlike the knife 502 in Figures 7A–7B, the rear end 804b of the knife 502 in Figures 8A–8B may include or otherwise define a shortened rear contour 814. The shortened rear contour 814 may prove advantageous when the knife 502 traverses the knife slot 508 (Figure 5). As shown in Figure 5, the knife slot 508 is curved and sometimes called a Maryland knife track. Other knife designs, such as the knife 502 in Figures 7A–7B, provide or exhibit a full trailing contour that allows the upper jaw 210 (Figures 2 and 4) to capture or contact the portion of the knife slot 508 provided to the knife slot 508 when the knife traverses the knife slot 508 during firing or retraction. Contact with the knife slot 508 during firing or retraction generates friction load and inefficiency.

[0070] In contrast, the shortened rear contour 814 of the knife 502 in Figures 8A and 8B provides a smaller surface area at the rear end 804b and is therefore less likely to capture or contact the portion of the knife slot 508 provided to the upper jaw 210 (Figures 2 and 4). More specifically, the shortened rear contour 814 allows the knife 502 to navigate the curved knife slot 508 more easily and without significant friction load, including a significant reduction in frictional resistance as it passes through the tissue. Furthermore, the shortened rear contour 814 can result in a significant reduction in sensitivity to non-vertical tissue cutting (e.g., curvature of the knife slot 508, blade tilt, misalignment, etc.). Moreover, the reduced sensitivity of the shortened rear contour 814 allows for larger manufacturing tolerances. Finally, the shortened rear contour 814 can potentially reduce the amount of tissue particles pulled back into the jaws 210, 212 (Figures 2 and 4) because there is less tissue accumulation.

[0071] In some embodiments, as shown, the shortened rear contour 814 may include a first arched surface 816a extending from the top 818 of the knife 502, the first arched surface 816a transitioning to a second arched surface 816b, and then to a third arched surface 816c. Thus, in at least one embodiment, the shortened rear contour 814 may include three consecutive arched surfaces 816a-c. As shown, the first arched surface 816a and the third arched surface 816c may each be convex, and the second arched surface 816 may be concave.

[0072] In one or more embodiments, the first straight surface 820a may be interposed between the first arched surface 816a and the second arched surface 816b, and the second straight surface 820b may be interposed between the second arched surface 816b and the third arched surface 816c. In at least one embodiment, the first straight surface 820a and the second straight surface 820b may extend perpendicularly to each other. Furthermore, in at least one embodiment, the third straight surface 820c may extend from the third arched surface 816c, and the third straight surface 820c may extend substantially parallel to the first straight surface 820a and perpendicular to the second straight surface 820b.

[0073] In some embodiments, the third straight surface 820c may extend substantially perpendicular to the centerline 810 of the drive rod 416. However, in other embodiments, the third straight surface 820c may extend at other angles with respect to the centerline 180 without departing from the scope of the present disclosure. In at least one embodiment, the third straight surface 820c may be used to assist in positioning the knife 502 within the knife housing 506 (Figures 5 and 6A-6B) or to function as a hard stop or overdrive prevention mechanism. More specifically, when the knife 502 retracts into the housing position, the third straight surface 820c may be configured to engage with a portion of the knife housing 506 within the cavity 602, as described above (Figures 6A-6B). However, in other embodiments, when the knife 502 retracts into the housing position, the first straight surface 820a may alternatively be used on the knife housing for retraction, hard stop, overdrive prevention, and positioning load.

[0074] Still referring to Figures 8A and 8B, in some embodiments, the bottom 822 (shown by the dashed line) of the knife 502 at the front end 804a (e.g., on the end tab 718) may be curved or otherwise radial. Having a curved bottom 822 may prove advantageous in helping to prevent the knife 502 from becoming trapped in the knife slot 508 (Figure 5) when the knife 502 is moved distally (i.e., in the "firing" direction). The curved bottom 822 may further reduce surface contact on the bottom of the knife 502 that could engage with the bottom of the knife slot 508.

[0075] In some embodiments, the end tab 718 may define a curved proximal end 824, which may prove advantageous in helping to prevent the knife 502 from becoming trapped in the knife slot 508 (Figure 5) when the knife 502 is moved distally (i.e., in the "firing" direction). The curved proximal end 824 may further help to reduce the drag of any tissue and / or fragments that may be present in the knife slot 508.

[0076] The embodiments disclosed herein include the following: A. An end effector for a surgical tool, comprising: a first jaw and a second jaw facing each other, and a knife slot defined in one or both of the first jaw and the second jaw; and a knife extending through the knife slot and operably connected to the knife rod in a retaining mechanism fixed to the distal end of a drive rod, wherein a central notch is defined within the retaining mechanism, and a locking mechanism is defined within the central notch to receive the knife for axial restraint of the knife to the retaining mechanism and the knife rod. B. A method for operating a surgical tool, comprising positioning the surgical tool adjacent to a patient for surgery, wherein the surgical tool comprises a drive housing, an elongated shaft extending from the drive housing, a drive rod extending from the drive housing within the elongated shaft, and an end effector positioned at the distal end of the elongated shaft, the end effector comprising opposing first jaws and second jaws, a knife slot defined in one or both of the first jaws and second jaws, and a knife fixed to the distal end of the knife rod in a holding mechanism and extendable through the knife slot. The method further comprises closing the opposing first jaws and second jaws to grasp tissue between the opposing first jaws and second jaws, and acting the drive rod to advance the knife through the knife slot to cut tissue, wherein a central notch is defined within the holding mechanism, and the knife defines a locking mechanism receivable within the central notch for axially constraining the knife to the holding mechanism and the knife rod. C. An end effector for a surgical tool, comprising: opposing first jaws and second jaws, and knife slots defined in one or both of the first jaws and second jaws; and a knife extending through the knife slots and operably coupled to the knife rod in a retaining mechanism fixed to the distal end of a drive rod, wherein the knife provides a blade at the front end of the knife and comprises a front cutting edge extending perpendicular to a sealing plane provided between the opposing first jaws and second jaws when the opposing first jaws and second jaws are closed, and an angled cutting edge extending from the front cutting edge at a transition point, wherein the angled cutting edge extends from the front cutting edge at an angle offset from perpendicular to the sealing plane. D. An end effector for a surgical tool, comprising: a first jaw and a second jaw facing each other, and a knife slot defined in one or both of the first jaw and the second jaw; and a knife extending through the knife slot and operably connected to the knife rod in a retaining mechanism fixed to the distal end of a drive rod, wherein the knife provides a front end and a rear end opposite to the front end, and the blade is provided at the front end and the rear end which defines a shortened rear contour defined by the front end and a first arched surface extending from the top of the knife and transitioning to a second arched surface which transitions to a third arched surface.

[0077] Each of embodiments A, B, C, and D may have one or more of the following additional elements in any combination: Element 1: The retaining mechanism is attached to the distal end of the drive rod via at least one of crimp engagements, weld interfaces, adhesive attachments, interlocking or shrink fittings, overmolding, one or more mechanical fasteners, and any combination thereof. Element 2: The locking mechanism is formed on the knife via at least one of laser cutting, wire electrical discharge machining, milling, chemical etching, water jetting, and stamping. Element 3: The locking mechanism extends into the central notch without contacting the bottom of the central notch, such that a gap is defined between the bottom of the central notch and the locking mechanism. Element 4: The knife is welded to the outer surface of the retaining mechanism. Element 5: The knife is welded to the outer surface of the retaining mechanism at a first weld located distal to the central notch and a second weld located proximal to the central notch. Element 6: The length of the distal weld is less than the length of the proximal weld. Element 7: The length from the proximal end of the central notch to the proximal end of the retaining function is longer than the length from the distal end of the central notch to the distal end of the retaining function. Element 8: The locking function is received within the central notch such that the distal end of the locking function contacts the distal end opposite the central notch. Element 9: Further includes an end notch defined at the distal end of the drive rod and extending through part of the retaining mechanism, and an end tab defined by the knife and sized to be received within the end notch to stabilize the knife laterally when mounted in the retaining mechanism. Element 10: The blade provided at the front end of the knife includes a front cutting edge extending perpendicular to the sealing plane provided between the opposing first and second jaws when the opposing first and second jaws are closed, and an angled cutting edge extending from the front cutting edge at a transition point, the angled cutting edge extending from the front cutting edge at an angle offset from perpendicular to the sealing plane. Element 11: When the knife is advanced within the knife slot, the transition point is located below the ceiling plane.Element 12: The knife provides a front end and a rear end opposite the front end, the blade provided at the front end and the rear end providing a rear end that defines a shortened rear contour, the shortened rear contour being defined by a first arched surface that extends from the top of the knife and transitions to a second arched surface that transitions to a third arched surface. Element 13: The shortened rear contour further includes a first straight surface interposed between the first and second arched surfaces, a second straight surface interposed between the second and third arched surfaces, and a third straight surface extending from the third arched surface. Element 14: The third straight surface extends perpendicular to the centerline of the drive rod. Element 15: The central notch extends into the drive rod.

[0078] Element 16: The knife is welded to the outer surface of the retaining mechanism at one or both of a first weld located distal to the central notch and a second weld located proximal to the central notch. Element 17: The locking mechanism is received within the central notch such that the distal end of the locking mechanism contacts the opposing distal end of the central notch, and the method further includes positioning the knife by acting on a drive rod to retract the knife into the knife housing, applying an axial load to the drive rod to axially engage the knife with a portion of the knife housing, and transmitting the resulting axial load from the knife to the drive rod in the locking mechanism. Element 18: The blade provided at the front end of the knife includes a front cutting edge extending perpendicular to a sealing plane provided between the opposing first and second jaws when the opposing first and second jaws are closed, and an angled cutting edge extending from the front cutting edge at a transition point, the angled cutting edge extending from the front cutting edge at an angle offset from perpendicular to the sealing plane, and the method further includes using the blade to cut tissue grasped between the opposing first and second jaws as the knife advances through the knife slot. Element 19: The knife provides a front end and a rear end opposite the front end, the blade provided at the front end, and the rear end defines a shortened rear contour defined by the first arched surface extending from the top of the knife and transitioning to a second arched surface transitioning to a third arched surface.

[0079] Element 20: When the knife is advanced within the knife slot, the transition point is positioned below the ceiling plane.

[0080] Element 21: The shortened rear contour further includes a first straight surface interposed between the first and second arched surfaces, a second straight surface interposed between the second and third arched surfaces, and a third straight surface extending from the third arched surface. Element 22: The third straight surface extends perpendicularly to the centerline of the drive rod.

[0081] As a non-limiting example, exemplary combinations applicable to A, B, C, and D include element 4 with element 5, element 5 with element 6, element 10 with element 11, element 12 with element 13, element 13 with element 14, and element 21 with element 22.

[0082] Accordingly, the systems and methods disclosed are well-adapted to achieve the results and benefits mentioned, as well as the inherent results and benefits therein. The teachings of this disclosure can be modified and implemented in equivalent ways that are evident to those skilled in the art who are interested in the teachings herein, although different; therefore, the specific embodiments disclosed above are merely illustrative. Furthermore, it is not intended to limit the details of the structures or designs shown herein other than those described in the following claims. Accordingly, the specific illustrative embodiments disclosed above can be modified, combined, or altered, and all such variations are considered to be within the scope of this disclosure. The systems and methods illustrated herein can be suitably implemented in the absence of any elements not specifically disclosed herein and / or any optional elements disclosed herein. Compositions and methods are described using the terms “comprising,” “containing,” or “including” various components and processes, but compositions and methods can also “consist essentially of” or “consist of” various components and processes. All numbers and ranges disclosed above may differ to some extent. Whenever a numerical range with lower and upper limits is disclosed, any number and any range that falls within that range is specifically disclosed. In particular, all ranges of values ​​(of form) disclosed herein ("about a to about b," or equivalently "about a to b (from approximately a to b)," or equivalently "about a to b (from approximately ab)") should be understood to describe all numbers and ranges that fall within a broad range of values. Furthermore, terms in the claims have plain and ordinary meanings unless explicitly and clearly defined otherwise by the patentee. In addition, when used in claims, the indefinite article "a" or "an" is defined herein to mean one or more of the elements it introduces.Where there is any inconsistency in the use of a word or term in this Specified Patent or other document that may be incorporated herein by reference, the definition consistent with this Specified Patent or other Patent or other Document should be adopted.

[0083] As used herein, the phrase “at least one of” preceding a list of items is accompanied by the terms “and” or “or” to separate any of the items, but modifies the list as a whole, rather than each individual component of the list (i.e., each item). The phrase “at least one of” allows for meanings including at least one of any of the items and / or at least one of any combination of the items and / or at least one of each of the items. For example, the phrases “at least one of A, B, and C” or “at least one of A, B, or C” mean A only, B only, or C only, any combination of A, B, and C, and / or at least one of each of A, B, and C, respectively.

[0084] [Implementation Method] (1) An end effector for a surgical tool, wherein the end effector is Opposing first jaws and second jaws, and knife slots defined in one or both of the first jaws and the second jaws, The system includes a knife that is extendable through the knife slot and operably connected to the knife rod in a holding mechanism fixed to the distal end of the drive rod, An end effector having a central notch defined within the retaining mechanism, and the knife defining a locking mechanism receivable within the central notch for axially restraining the knife to the retaining mechanism and the knife rod. (2) The end effector according to Embodiment 1, wherein the retaining mechanism is attached to the distal end of the drive rod via at least one of a crimp engagement, a weld interface, adhesive attachment, a press fit or shrink fit, an overmolding, one or more mechanical fasteners, and any combination thereof. (3) The end effector according to Embodiment 1 or Embodiment 2, wherein the locking mechanism is formed on the knife by at least one of laser cutting, wire electrical discharge machining, milling, chemical etching, water jetting, and stamping. (4) The end effector according to any one of embodiments 1 to 3, wherein the locking mechanism extends into the central notch without contacting the bottom of the central notch, such that a gap is defined between the bottom of the central notch and the locking mechanism. (5) The end effector according to any one of embodiments 1 to 4, wherein the knife is welded to the outer surface of the holding mechanism.

[0085] (6) The end effector according to Embodiment 5, wherein the knife is welded to the outer surface of the holding mechanism at a first weld located distal to the central notch and a second weld located proximal to the central notch. (7) The end effector according to Embodiment 6, wherein the length of the distal weld is smaller than the length of the proximal weld. (8) The end effector according to any one of embodiments 1 to 7, wherein the length from the proximal end of the central notch to the proximal end of the retaining mechanism is longer than the length from the distal end of the central notch to the distal end of the retaining mechanism. (9) The end effector according to any one of embodiments 1 to 8, wherein the locking mechanism is received within the central notch such that the distal end of the locking mechanism contacts the distal end opposite the central notch. (10) An end notch defined at the distal end of the drive rod and extending through a part of the holding mechanism, An end effector according to any one of embodiments 1 to 9, further comprising: an end tab defined by the knife and sized to be received within the end notch to stabilize the knife laterally when attached to the retaining mechanism.

[0086] (11) The blade provided at the front end of the knife is A forward cutting edge extending perpendicular to the sealing plane provided between the opposing first jaws and the second jaws when the opposing first jaws and the second jaws are closed, An end effector according to any one of embodiments 1 to 10, comprising an angled cutting edge extending from the front cutting edge at a transition point, wherein the angled cutting edge extends from the front cutting edge at an angle offset from perpendicular to the sealing plane. (12) The end effector according to embodiment 11, wherein when the knife is advanced within the knife slot, the transition point is positioned below the sealing plane. (13) The end effector according to any one of embodiments 1 to 12, wherein the knife provides a front end and a rear end opposite to the front end, and a blade is provided at the front end, the rear end defining a shortened rear contour, the shortened rear contour being defined by a first arched surface extending from the top of the knife and transitioning to a second arched surface that transitions to a third arched surface. (14) The shortened rear contour is A first straight surface interposed between the first arch-shaped surface and the second arch-shaped surface, A second straight surface interposed between the second arch-shaped surface and the third arch-shaped surface, The end effector according to embodiment 13, further comprising a third straight surface extending from the third arcuate surface. (15) The end effector according to embodiment 14, wherein the third straight surface extends perpendicularly with respect to the center line of the drive rod.

[0087] (16) The end effector according to any one of embodiments 1 to 15, wherein the central notch extends into the drive rod. (17) A method for operating a surgical tool, Positioning the surgical tool adjacent to the patient for surgery, the surgical tool includes a drive housing, an elongated shaft extending from the drive housing, a drive rod extending from the drive housing within the elongated shaft, and an end effector positioned at the distal end of the elongated shaft, the end effector is Facing each other were the first and second Joes, A knife slot defined in one or both of the first jaw and the second jaw, The holding mechanism includes a knife fixed to the distal end of the knife rod and extending through the knife slot, The opposing first jaws and the second jaws are closed, thereby gripping the tissue between the opposing first jaws and the second jaws, A method comprising: acting the drive rod to advance the knife through the knife slot to cut the tissue, wherein a central notch is defined within the retaining mechanism, and the knife defines a locking mechanism receivable within the central notch for axially restraining the knife to the retaining mechanism and the knife rod. (18) The method according to embodiment 17, wherein the knife is welded to the outer surface of the retaining mechanism at one or both of the first weld located distal to the central notch and the second weld located proximal to the central notch. (19) The locking mechanism is received within the central notch such that the distal end of the locking mechanism contacts the distal end opposite the central notch, and the method is The knife is positioned by operating the drive rod to retract the knife into the knife housing, In order to engage the knife with a portion of the knife housing in the axial direction, an axial load is applied to the drive rod, The method according to Embodiment 17 or Embodiment 18, further comprising transmitting the resulting axial load from the knife to the drive rod in the locking mechanism. (20) The blade provided at the front end of the knife includes a front cutting edge extending perpendicular to a sealing plane provided between the opposing first jaws and the second jaws when the opposing first jaws and the second jaws are closed, and an angled cutting edge extending from the front cutting edge at a transition point, wherein the angled cutting edge extends from the front cutting edge at an angle offset from perpendicular to the sealing plane, and the method is The method according to any one of embodiments 17 to 19, further comprising using the blade to cut tissue gripped between the opposing first jaws and the second jaws as the knife advances through the knife slot.

[0088] (21) The method according to any one of embodiments 17 to 20, wherein the knife provides a front end and a rear end opposite to the front end, and a blade is provided at the front end, and the rear end defines a shortened rear contour defined by a first arched surface that extends from the top of the knife and transitions to a second arched surface that transitions to a third arched surface. (22) An end effector for a surgical tool, wherein the end effector is Opposing first jaws and second jaws, and knife slots defined in one or both of the first jaws and the second jaws, The knife includes a knife that is extendable through the knife slot and operably connected to the knife rod in a retaining mechanism fixed to the distal end of the drive rod, the knife providing a blade at the front end of the knife, A forward cutting edge extending perpendicular to the sealing plane provided between the opposing first jaws and the second jaws when the opposing first jaws and the second jaws are closed, An end effector comprising an angled cutting edge extending from the front cutting edge at a transition point, wherein the angled cutting edge extends from the front cutting edge at an angle offset from perpendicular to the sealing plane. (23) The end effector according to embodiment 22, wherein when the knife is advanced within the knife slot, the transition point is positioned below the sealing plane. (24) An end effector for a surgical tool, wherein the end effector is Opposing first jaws and second jaws, and knife slots defined in one or both of the first jaws and the second jaws, A knife that is extendable through the knife slot and operably connected to the knife rod in a retaining mechanism fixed to the distal end of the drive rod, wherein the knife provides a front end and a rear end opposite to the front end, An end effector comprising: the front end and a blade provided at the rear end that defines a shortened rear contour, defined by a first arched surface extending from the top of the knife and transitioning to a second arched surface that transitions to a third arched surface. (25) The shortened rear contour is A first straight surface interposed between the first arch-shaped surface and the second arch-shaped surface, A second straight surface interposed between the second arch-shaped surface and the third arch-shaped surface, The end effector according to embodiment 24, further comprising a third straight surface extending from the third arc-shaped surface.

[0089] (26) The end effector according to embodiment 25, wherein the third straight surface extends perpendicularly with respect to the center line of the drive rod.

Claims

1. An end effector for a surgical tool, wherein the end effector is Opposing first jaws and second jaws, and knife slots defined in one or both of the first jaws and the second jaws, The system includes a knife that is extendable through the knife slot and operably connected to the knife rod in a holding mechanism fixed to the distal end of the drive rod, An end effector having a central notch defined within the retaining mechanism, and the knife defining a locking mechanism receivable within the central notch for axially restraining the knife to the retaining mechanism and the knife rod.

2. The end effector according to claim 1, wherein the retaining mechanism is attached to the distal end of the drive rod via at least one of crimp engagement, welding interface, adhesive attachment, interlocking or shrink fitting, overmolding, one or more mechanical fasteners, and any combination thereof.

3. The end effector according to claim 1, wherein the locking mechanism is formed on the knife via at least one of laser cutting, wire electrical discharge machining, milling, chemical etching, water jetting, and stamping.

4. The end effector according to claim 1, wherein the locking mechanism extends into the central notch without contacting the bottom of the central notch, such that a gap is defined between the bottom of the central notch and the locking mechanism.

5. The end effector according to claim 1, wherein the knife is welded to the outer surface of the holding mechanism.

6. The end effector according to claim 5, wherein the knife is welded to the outer surface of the holding mechanism at a first weld located distal to the central notch and a second weld located proximal to the central notch.

7. The end effector according to claim 6, wherein the length of the distal weld is smaller than the length of the proximal weld.

8. The end effector according to claim 1, wherein the length from the proximal end of the central notch to the proximal end of the retaining mechanism is longer than the length from the distal end of the central notch to the distal end of the retaining mechanism.

9. The end effector according to claim 1, wherein the locking mechanism is received within the central notch such that the distal end of the locking mechanism contacts the distal end opposite the central notch.

10. An end notch defined at the distal end of the drive rod and extending through a part of the holding mechanism, The end effector according to claim 1, further comprising: an end tab defined by the knife and sized to be received within the end notch to stabilize the knife laterally when attached to the retaining mechanism.

11. The blade provided at the front end of the knife is A forward cutting edge extending perpendicular to the sealing plane provided between the opposing first jaws and the second jaws when the opposing first jaws and the second jaws are closed, The end effector according to claim 1, comprising an angled cutting edge extending from the front cutting edge at a transition point, wherein the angled cutting edge extends from the front cutting edge at an angle offset from perpendicular to the sealing plane.

12. The end effector according to claim 11, wherein when the knife is advanced within the knife slot, the transition point is positioned below the sealing plane.

13. The end effector according to claim 1, wherein the knife provides a front end and a rear end opposite to the front end, and a blade is provided at the front end, the rear end defining a shortened rear contour, the shortened rear contour being defined by a first arched surface extending from the top of the knife and transitioning to a second arched surface that transitions to a third arched surface.

14. The shortened rear contour is A first straight surface interposed between the first arch-shaped surface and the second arch-shaped surface, A second straight surface interposed between the second arch-shaped surface and the third arch-shaped surface, The end effector according to claim 13, further comprising a third straight surface extending from the third arc-shaped surface.

15. The end effector according to claim 14, wherein the third straight surface extends perpendicularly with respect to the center line of the drive rod.

16. The end effector according to claim 1, wherein the central notch extends into the drive rod.

17. An end effector for a surgical tool, wherein the end effector is Opposing first jaws and second jaws, and knife slots defined in one or both of the first jaws and the second jaws, The knife includes a knife that is extendable through the knife slot and operably connected to the knife rod in a retaining mechanism fixed to the distal end of the drive rod, the knife providing a blade at the front end of the knife, A forward cutting edge extending perpendicular to the sealing plane provided between the opposing first jaws and the second jaws when the opposing first jaws and the second jaws are closed, An end effector comprising an angled cutting edge extending from the front cutting edge at a transition point, wherein the angled cutting edge extends from the front cutting edge at an angle offset from perpendicular to the sealing plane.

18. The end effector according to claim 17, wherein when the knife is advanced within the knife slot, the transition point is positioned below the sealing plane.

19. An end effector for a surgical tool, wherein the end effector is Opposing first jaws and second jaws, and knife slots defined in one or both of the first jaws and the second jaws, A knife that is extendable through the knife slot and operably connected to the knife rod in a retaining mechanism fixed to the distal end of the drive rod, wherein the knife provides a front end and a rear end opposite to the front end, An end effector comprising: the front end and a blade provided at the rear end that defines a shortened rear contour, defined by a first arched surface extending from the top of the knife and transitioning to a second arched surface that transitions to a third arched surface.

20. The shortened rear contour is A first straight surface interposed between the first arch-shaped surface and the second arch-shaped surface, A second straight surface interposed between the second arch-shaped surface and the third arch-shaped surface, The end effector according to claim 19, further comprising a third straight surface extending from the third arc-shaped surface.

21. The end effector according to claim 20, wherein the third straight surface extends perpendicularly with respect to the center line of the drive rod.

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